Android Instrumented Tests on Firebase Test Lab with Travis CI

If Travis CI is your Continuous Integration service, running Instrumented Tests right on the Travis CI build is a bad idea. You can only use ARM emulator on Travis CI, which is very slow. You might fail your tests because of Activity not launched within 45 seconds.
Not even mention you have to setup emulator environment on Travis CI build which takes extra 10 minutes.

Travis Build Matrix

If you had Unit Test already, use Travis CI build matrix feature is the best practice to separate unit tests and instrumented test.